Getting to move object with mouse position?

I have tried to make a card game where you can click and drag the cards around, but i can't seem to figure out how to move the object, with the mouse position without flinging miles away in the game scene. Can someone help me out, i am in 2nd of college (english) and know moderate jarva scripting.

He is the script i borrowed off someone else can someone modify it and get the cards to follow the mouse position.

 #pragma strict
  
 // Attach this script to an orthographic camera.
  
 private var object : Transform;    // The object we will move.
  
 private var offSet : Vector3;    // The object's position relative to the mouse position.
  
  
  
 function Update () 
 {
  
     var ray = camera.ScreenPointToRay(Input.mousePosition);    // Gets the mouse position in the form of a ray.
  
     if (Input.GetButtonDown("Fire1")) 
     {    // If we click the mouse...
  
         if (!object) 
         {    // And we are not currently moving an object...
  
             var hit : RaycastHit;
  
             if (Physics.Raycast(ray, hit, Mathf.Infinity) && (hit.collider.tag == "BlueCard")) 
             {    // Then see if an object is beneath us using raycasting.
  
                 object = hit.transform;    // If we hit an object then hold on to the object.
  
                 offSet = object.position-ray.origin;    // This is so when you click on an object its center does not align with mouse position.
  
             }
  
         }
  
     }
  
     else if (Input.GetButtonUp("Fire1")) 
     {
  
         object = null;    // Let go of the object.
  
     }
  
     if (object) 
     
     {
  
         object.position = Vector3(ray.origin.x+offSet.x, object.position.y, ray.origin.z+offSet.z);    // Only move the object on a 2D plane.
  
     }
  
 }